Very good shot, the yellow shirt gives it a vibrance and energy. And the fish isn't that small, it looks good for a couple of mouthfuls :-) And of course huge congrats on getting published!
I feel some space to the left of this image, just to move the boy closer to the third line, would have helped balance this out a bit more. At the moment, he is very close to the side of the image. The shaddow accross his leg is annoying, and this follows through the foreground.
The colours in this also seem like they could have been improved during Post Processing